/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.library.drepair.util;

import org.apache.commons.lang3.tuple.Pair;
import org.apache.commons.math3.stat.descriptive.rank.Median;
import org.apache.iotdb.library.util.Util;
import org.apache.iotdb.udf.api.access.RowIterator;
import org.apache.iotdb.udf.api.exception.UDFException;

import java.util.ArrayList;
import java.util.Arrays;

// Reference to Screen.java
public class ScreenFill extends ValueFill {

    private double smin, smax;
    private double w;

    public ScreenFill(RowIterator dataIterator) throws Exception {
        super(dataIterator);
        setParameters();
    }

    @Override
    public long[] getTime() {
        return super.getTime();
    }

    @Override
    public double[] getFilled() {
        return super.getFilled();
    }

    @Override
    public void calMeanAndVar() throws UDFException {
        super.calMeanAndVar();
    }

    @Override
    public void fill() {
        ArrayList<Pair<Long, Double>> ans = new ArrayList<>();
        int currentIndex = 0;
        while (currentIndex < n) {
            ans.add(Pair.of(time[currentIndex], original[currentIndex]));
            if (Double.isNaN(original[currentIndex])) {
                int startIndex = currentIndex;
                long fillTime = time[currentIndex];
                int nextIndex = -1;
                currentIndex++;
                while (currentIndex < n && fillTime + w >= time[currentIndex]) {
                    ans.add(Pair.of(time[currentIndex], original[currentIndex]));
                    if (Double.isNaN(original[currentIndex]) && nextIndex == -1) {
                        nextIndex = currentIndex;
                    }
                    currentIndex++;
                }
                local(ans, startIndex);
                if (nextIndex > 0) {
                    while (currentIndex > nextIndex) {
                        ans.remove(currentIndex - 1);
                        currentIndex--;
                    }
                }
            } else {
                currentIndex++;
            }
        }
        int k = 0;
        for (Pair<Long, Double> p : ans) {
            this.repaired[k] = p.getRight();
            k++;
        }
    }

    private double getMedian(ArrayList<Pair<Long, Double>> list, int index) {
        int m = 0;
        while (index + m + 1 < list.size()
                && list.get(index + m + 1).getLeft() <= list.get(index).getLeft() + w) {
            m++;
        }
        int count = 0;
        for (int i = 1; i <= m; i++) {
            if (!Double.isNaN(list.get(index + i).getRight())) {
                count++;
            }
        }
        double x[] = new double[2 * count];
        int temp_count = 0;
        for (int i = 1; i <= m; i++) {
            if (!Double.isNaN(list.get(index + i).getRight())) {
                x[temp_count] =
                        list.get(index + i).getRight()
                                + smin * (list.get(index).getLeft() - list.get(index + i).getLeft());
                x[temp_count + count] =
                        list.get(index + i).getRight()
                                + smax * (list.get(index).getLeft() - list.get(index + i).getLeft());
                temp_count++;
            }
        }
        Arrays.sort(x);
        return x[count];
    }

    private double getRepairedValue(ArrayList<Pair<Long, Double>> list, int index, double mid) {
        double xmin =
                list.get(index - 1).getRight()
                        + smin * (list.get(index).getLeft() - list.get(index - 1).getLeft());
        double xmax =
                list.get(index - 1).getRight()
                        + smax * (list.get(index).getLeft() - list.get(index - 1).getLeft());
        double temp = mid;
        temp = Math.min(xmax, temp);
        temp = Math.max(xmin, temp);
        return temp;
    }

    private void local(ArrayList<Pair<Long, Double>> list, int index) {
        double mid = getMedian(list, index);
        if (index == 0) {
            list.set(index, Pair.of(list.get(index).getLeft(), mid));
        } else {
            double temp = getRepairedValue(list, index, mid);
            list.set(index, Pair.of(list.get(index).getLeft(), temp));
        }
    }

    private void setParameters() {
        double[] speed = Util.speed(original, time);
        Median median = new Median();
        double mid = median.evaluate(speed);
        double sigma = Util.mad(speed);
        smax = mid + 3 * sigma;
        smin = mid - 3 * sigma;
        double[] interval = Util.variation(time);
        w = 5 * median.evaluate(interval);
    }
}
